Distributed control systems (DCS) are used in a variety of process industries including chemical, petrochemical, refining, pharmaceutical, food and beverage, power, cement, water and wastewater, oil and gas, pulp and paper, and steel, and are used to control batch, fed-batch, and continuous processes operating at a single site or at remote locations. Process plants typically include one or more process controllers communicatively coupled to one or more computing devices (e.g., field devices, operator workstations) via analog, digital or combined analog/digital buses, or via a wireless communication link or network. Collectively, the various devices perform monitoring, control, and data collection functions to control the process, safety shutdown systems, fire and gas detection systems, machine health monitoring systems, maintenance systems, decision support, and other systems.
Field devices, which may be, for example, valves, valve positioners, switches and transmitters (e.g., temperature, pressure, level and flow rate sensors), are located within the process environment and generally perform physical or process control functions such as opening or closing valves, measuring process parameters, etc. to control one or more processes executing within the process plant or system. Smart field devices, such as the field devices conforming to the well-known Fieldbus protocol may also perform control calculations, alarming functions, and other control functions commonly implemented within the controller. The process controllers, which are also typically located within the plant environment, receive signals indicative of process measurements made by the field devices and/or other information pertaining to the field devices and execute a controller application that runs, for example, different control modules which make process control decisions, generate control signals based on the received information and coordinate with the control modules or blocks being performed in the field devices, such as HART®, WirelessHART®, and FOUNDATION® Fieldbus field devices. The control modules in the controller send the control signals over the communication lines or links to the field devices to thereby control the operation of at least a portion of the process plant or system.
Information from the field devices and the controller is usually made available over a data highway to one or more other hardware devices, such as operator workstations, personal computers or computing devices, data historians, report generators, centralized databases, or other centralized administrative computing devices that are typically placed in control rooms or other locations away from the harsher plant environment. Each of these hardware devices typically is centralized across the process plant or across a portion of the process plant. These hardware devices run applications that may, for example, enable an operator to perform functions with respect to controlling a process and/or operating the process plant, such as changing settings of the process control routine, modifying the operation of the control modules within the controllers or the field devices, viewing the current state of the process, viewing alarms generated by field devices and controllers, simulating the operation of the process for the purpose of training personnel or testing the process control software, keeping and updating a configuration database, etc. The data highway utilized by the hardware devices, controllers and field devices may include a wired communication path, a wireless communication path, or a combination of wired and wireless communication paths.
As an example, the DeltaV™ control system, sold by Emerson Process Management, includes multiple applications stored within and executed by different devices located at diverse places within a process plant. A configuration application, which resides in one or more workstations or computing devices, enables users to create or change process control modules and download these process control modules via a data highway to dedicated distributed controllers. Typically, these control modules are made up of communicatively interconnected function blocks, which are objects in an object oriented programming protocol that perform functions within the control scheme based on inputs thereto and that provide outputs to other function blocks within the control scheme. The configuration application may also allow a configuration engineer to create or change operator interfaces which are used by a viewing application to display data to an operator and to enable the operator to change settings, such as setpoints, within the process control routines. Each dedicated controller and, in some cases, one or more field devices, stores and executes a respective controller application that runs the control modules assigned and downloaded thereto to implement actual process control functionality. The viewing applications, which may be executed on one or more operator workstations (or on one or more remote computing devices in communicative connection with the operator workstations and the data highway), receive data from the controller application via the data highway and display this data to process control system designers, operators, or users using the user interfaces, and may provide any number of different views, such as an operator's view, an engineer's view, a technician's view, etc. A data historian application is typically stored in and executed by a data historian device that collects and stores some or all of the data provided across the data highway while a configuration database application may run in a still further computer attached to the data highway to store the current process control routine configuration and data associated therewith. Alternatively, the configuration database may be located in the same workstation as the configuration application.
For a variety of reasons, access to data of a process event (e.g., status of a field device) occurring at the process control system has traditionally been available while on the process plant premises and/or while using a device connected to the data highway that couples the operator workstations, controllers, data historians, and other equipment. However, access to data of a non-process event (e.g., severe weather) affecting a process control system, and solutions thereof that take actionable steps upon receiving data of a non-process event, have largely been unaddressed.
Notifying plant personnel of non-process events is a particular safety concern with respect to process control systems. For example, notifying users, such as engineers and technicians, to evacuate a plant in response to dangers resulting from non-process events of a process plant has traditionally been handled by manually contacting such users, such as via their mobile devices or via email. Sometimes, notifying plant personnel may be cascaded in order of seniority (i.e., a site-wide operator may make a phone call to a regional operator assigned to a portion of the plant, who may contact other users under his supervision), which may delay propagation of evacuation information to some users. Controlling field devices (e.g., shutting down field devices) in response to non-process events may also provide benefits to the process control systems. There is currently no organized manner of detecting non-process event in real-time within the process plant or within some proximity of the process plant, such as detecting severe weather in real time, much less an easily implementable system for detecting non-process events and alerting personnel of the non-process events on a system-level basis.